Field of the Invention
The present invention relates to the field of cancer prevention by use of agents that have been found to have the ability to intercept cancerous or pre-cancerous cells by activating or enhancing DNA repair activity of altered or damaged DNA.
Related Art
Presented below is background information on certain aspects of the present invention as they may relate to technical features referred to in the detailed description, but are not necessarily described in detail. That is, individual compositions or methods used in the present invention may be described in greater detail in the publications and patents discussed below, which may provide further guidance to those skilled in the art for making or using certain aspects of the present invention as claimed. The discussion below should not be construed as an admission as to the relevance or the prior art effect of the patents or publications described.
Oxidative DNA damage (ODD) constitutes the majority of DNA damage in human cells due to reactive oxygen species (ROS), which are genotoxic agents generated endogenously by metabolism and other biological processes. ODD typically occurs as single-base alterations (i.e. lesions) and undergoes repair via the base excision DNA repair (BER) pathway. When left unrepaired, ODD results in mutagenesis. For example, the most common ODD lesion, 8-oxoguanine (8-OG), can mispair and result in GC→TA transversions. Alternatively, ODD converts to single- or double-stranded breaks and results in genomic instability. Overall, these events contribute to the initiation, progression, and maintenance of various malignancies, including breast cancer. However, little is known about the regulation of ODD.
To reduce the risk of developing cancer, chemopreventative drugs may be used by high-risk patients. Two such drugs, tamoxifen and raloxifene (Evista), are currently used in the prevention of invasive breast cancer. Both of these drugs belong to a class known as selective estrogen receptor modulators (SERMs), which block the effects of estrogen in the breast and other tissues. Toremifene, another SERM class drug, is used in advanced metastatic breast cancer. None of these drugs, however, are known to upregulate a cellular DNA repair mechanism.